Scala map and filter methods

map(func) and filter(func) Both are first class methods. First class methods take function as input parameter or output as function.
Functional programming: Programming focusing on a function is used as input parameter of another function or methods or as output of another function or method

map(func) method:

res0: Array[Int] = Array(2, 3, 4, 5, 6)


res2: Array[Int] = Array(2, 4)